Alternator with voltage regulation

Abstract

The present invention relates to an alternator to be electrically connected to a load, the alternator including a rotor including: a rotary field, an excitation winding, a dissipative component and a switchover system allowing the rotary field to be connected selectively to the excitation winding or to the dissipative component, and a controller controlling the switchover system so as to regulate the current in the rotary field and, in response to a reduction in the load applied to the alternator, connects the dissipative component to the rotary field to dissipate the inductive energy that has built up in the rotary field.

1 . Alternator to be electrically linked to a load, the alternator comprising:
 a rotor comprising:
 a rotary field of a primary machine, 
 an exciting armature 
 a dissipative component, and 
 a switching system making it possible to selectively link the rotary field to the exciting armature and to the dissipative component, and 
   a controller controlling the switching system so as to regulate current in the rotary field by pulse width modulation and, in response to a reduction in the load applied to the alternator, link the dissipative component to the rotary field to dissipate inductive energy stored in the rotary field, the duty cycle and the pulse width modulation being a function of the output voltage of the primary machine.   
     
     
         2 . Alternator according to  claim 1 , the duty cycle of the pulse width modulation being a function of the current in the rotary field. 
     
     
         3 . Alternator according to  claim 1 , the dissipative component being purely ohmic. 
     
     
         4 . Alternator according to  claim 1 , the controller being incorporated in the rotor. 
     
     
         5 . Alternator according to  claim 1 , the rotor including a rectifier supplying, from the exciting armature a DC bus to which the switching system is linked. 
     
     
         6 . Alternator according to  claim 5 , the DC bus including a filtering capacitor. 
     
     
         7 . Alternator according to  claim 1 , the DC bus being non-filtered. 
     
     
         8 . Alternator according to  claim 1 , the switching system including an H-configuration bridge outputting the rotary field. 
     
     
         9 . Alternator according to  claim 1 , the power for the transmission module and the controller of the rotor being supplied from the exciting armature voltage rectified by the rectifier. 
     
     
         10 . Alternator according to  claim 1 , controller, controlling the switching system, comprising at least one integrated circuit. 
     
     
         11 . Alternator according to  claim 1 , the rectifier, the switching system and the controller being mounted on segments. 
     
     
         12 . Alternator according to  claim 1 , the rectifier, the switching system and the controller being mounted on one or more modules fixed directly onto the rotor, notably through one or more insulating supports. 
     
     
         13 . Alternator according to  claim 1 , including a current sensor for measuring the current in the rotary field and for transmitting to the controller and/or to a voltage regulator the value of the duly measured current. 
     
     
         14 . Alternator according to  claim 1 , including an exciting inductor comprising permanent magnets. 
     
     
         15  . Alternator according to  claim 4 , including a coiled exciting inductor. 
     
     
         16 . Alternator according to  claim 4 , including a system for wireless transmission between controller and a voltage regulator at the stator of the alternator. 
     
     
         17 . Alternator according to  claim 16 , including a temperature sensor for the rotary field, the measured value being transmitted by the wireless transmission system to the voltage regulator to the stator. 
     
     
         18 . Alternator according to  claim 17 , the duty cycle of the pulse width modulation being a function of the temperature of the rotary field. 
     
     
         19 . Alternator according to  claim 1 , the connection of the dissipative component to the rotary field being established when the duty cycle of the pulse width modulation is zero and ceasing when this duty cycle becomes non-zero again. 
     
     
         20 . Method for reducing the load shedding response time of an alternator according to  claim 1 , in which:
 in response to the detection of a reduction in the load applied to the alternator, the controller acts by pulse width modulation on the switching system to link the rotary field to the dissipative component, in order to dissipate inductive energy stored in the rotary field,   the duty cycle of the pulse width modulation being a function of the output voltage of the primary machine,   
     
     
         21 . Method according to  claim 20 , in which, in response to the detection of a reduction in the load applied to the alternator, the voltage at the terminals of the rotary field is reversed, reducing the current in said rotary field. 
     
     
         22 . Method for reducing the load impact response time of an alternator according to  claim 1 , in which:
 in response to the detection of an increase in the load applied to the alternator, the controller acts by pulse width modulation on the switching system by adjusting the duty cycle of the pulse width modulation in order to increase the current in the rotary field and to reduce the voltage drop,   the duty cycle of the pulse width modulation being a function of the output voltage of the primary machine.